Extensible-retractile structure



May 28, 1968 E. I. ROBINSKY EXTENSIBLE-RETRACTILE STRUCTURE 2Sheets-Sheet 1 Filed July 18, 196

' .May 28, 1968 5. 1. ROBINSKY I 3,

EXTENSIBLE-RETRACTILE STRUCTURE Filed July 18, 1966 l 2 Sheets-Sheet 2INVENTOK ELI 1v msmsxy BY v .l ATTORNEY United States Patent 3,385,397EXTENSIBLE-RETRACTILE STRUCTURE Eli I. Robinsky, 301 Jedburgh Road,Toronto, Ontario, Canada Filed July 18, 1966, Ser. No. 566,076 12Claims. (Cl. 182-41) ABSTRACT OF THE DISCLOSURE A ladder, tower or thelike which has each of its upright members formed from a fiat sheet ofresilient material which is preformed to coil into a tube when unwoundfrom a flat roll and when rewound, to automatically uncoil. Each rail ofeach pair of rails, such as a ladder is wound into a separate roll. Eachpair of rails are secured together by uniformly spaced crossbars. Whenformed into tubes an overlapping edge portion of each tube wedgesbetween the cross bar and the other edge of the same tube to preventrelative movement both longitudinally and circumferentially betweenoverlapping portions of the tubular rail to prevent lateral distortionor deflection of the walls under load. The same members are used to makean upright structure of three or more upright members. In this case, therails are unwound from their roll so that adjacent tubes will locktogether, one inside the other, to form a unitary structure.

Extensible-retractile structures have already been proposed and one suchstructure is set forth in U.S. Patent 3,199,627 dated Aug. 10, 1965 toAladin Saders Inc. That structure comprised a ladder which was formed ofa plurality of inter-connected sections which could be rolled up into arelatively small package. Such a structure is complex and expensive tomanufacture. The numerous joints limit its usefulness and will have anumber of objections apparent to those familiar with this field.

A novel feature of the present invention and one of its advantages isthat it can be wound up on a reel for storage and when it is unwound itwill automatically form into a rugged and stable structure ashereinafter described.

Another advantage of the invention is that it provides anextensible-retractile structure, such as an extension ladder, of anypractical length without any transverse joints which will adverselyaffect its rigidity transversely or longitudinally. The foregoingfeatures distinguish the present invention from the conventional type ofextension ladder presently in use and which extension ladder is made upof several sections, which telescopically fit together, each sectionbeing anywhere from 20* to 80 feet in length to obtain the requiredlength; and also the roll-up type of ladder disclosed in US. Patent3,199,627.

Another feature of the present invention is that a plurality of theextensible-retractile structures can be readily combined to form a toweras hereinafter described.

Other and further advantages of this invention will be explained in thefollowing description of a preferred embodiment in which it is used forthe manufacture of an extension ladder or the alternative structure inwhich three such ladders are combined into a unitary structure to form,for example, an extensible-retractile tower or mast.

In the drawings:

FIGURE 1 is a perspective view illustrating the present inventionconstructed as an extensible-retractile ladder;

FIGURE 2 is a fragmentary sectional view on the line 22 of FIGURE 1;

FIGURE 3 is a cross-sectional view taken on the line 3-3 of FIGURE 1;

FIGURE 4 is a cross-sectional view taken on the line 4-4 of FIGURE 1;

3,385,397 Patented May 28, 1968 FIGURE 5 is a plan view illustrating theladder in which the rails and rungs are made from one piece of sheetsteel;

FIGURE 6 is an alternative structure in which three ladders similar tothe one described in conjunction with FIGURES l-5 are combined to form athree sided structure, e.g., a mast.

FIGURE 7 is a .plan view looking down on the structure shown in FIGURE6.

The roll-up ladder illustrated in the drawings comprises a base 10,ladder support members 11, a rotatable storage reel 12, a pair oflongitudinally extensible-retractile tubular rails 13, 14 which areconnected together by rungs 15 in spatial relationship and a releasablelocking member, to be described for locking the rails when extended, asillustrated in FIGURE 1, against downward movement when a load such asthe weight of a man, is applied to the rungs 15. These components willnow be particularly described as to their construction and relationshipto one another.

The base 10 is fabricated from any suitable material such as angle iron,angle aluminum, etc, and comprises the horizontal framing members 17,18, 19, 20; upright frame members 21, 22, 23, 24 forming a skeletalframework, the top ends of the upright members 21, 22, 23, 24, beingtied together by a plurality of plates 25, 26, 27 through which the siderails 13, 14 are slidably projected as herein described, the platesproviding a support for the lower end of the ladder rails and also todirect the rails in an upright direction as they are extended byunwinding from the storage reel 12 which is supported by said frame.

The storage reel 12 is rotatably supported on the crossframe members 28,29 of the base as shown. The reel is provided with some means forrotating it in the proper direction to wind and unwind the ladder ashereinafter described. In the present illustration this means comprisesa crank 30 which is manually operated to turn the reel. However, it isapparent that the crank 30 could be replaced by some power means such asan electric motor suitably geared to the storage reel to rotate it inany direction desired.

The ladder per se comprises the pair of spaced apart rails 13, 14connected together by a plurality of rungs 15, the rungs being connectedto the rails by rivets, welding or other suitable connecting means. Eachof the rails 13, 14 are made of a thin strip of resilient sheetmaterial, such as sheet steel, each rail being pre-formed to coil intooverlapping cylindrical tube about the longitudinal axis when unwoundfrom the reel as illustrated. The bottom end of each of the rails 13, 14is fastened in a flattened condition to the reel as shown. Forconvenience in description the bottom ends of the respective rails areidentified as the lead-in ends 31, 32 of the rails 13, 14 respectively.If desired the reel can be dispensed with and the rails rolled up bysimply manipulating the ends 31, 32 into a flat position and thenrolling up the ladder which during the rolling will automatically forcethe tubular rails to a fiat position. When the rails are flat they areflexible and can be rolled but when tubular as hereinbefore stated therails are rigid.

Each of the plates 25, 26, 27 as will be seen in the drawings, areprovided with aligned guideways 33, 34 through which the rails 13, 14when tubular will pass, the guideways associated with each plate beinginterconnected by slots 36, 37, 38 respectively through which the rungs15 can pass as the ladder is extended and retracted.

It is desirable to prevent the downward movement of the rails underload, and a convenient way of doing this is by 'a removable U-strap 39which straddles the slot 37 with one of the rungs 15 engaged between theupper and lower arms of the U-strap. The U-strap 39 is mounted so thatit can be easily disengaged from the rung to permit the raising and thelowering of the ladder.

If preferred, the ladder may be fabricated from a single sheet ofmaterial of the required length and width. As illustrated in FIGURE 5,when the rails and rungs are fabricated from a single sheet of material,the first operation is to form the rungs by cutting the central portionof the sheet to leave the longitudinal edge portions which willeventually be formed into the tubular rails 13, 14 connected together bytransverse strips spaced apart the required distance to form the rungs15. The cut central portion is folded over the transverse strips to formthe rigid rungs 15.

The operation of the extensible-retractile ladder is very simple andrequires little explanation. The lead-in ends 31, 32 are attached in aflattened condition to the reel 12. No guiding means is necessary forflattening or reforming the rails 13, 14 during the retraction orextension. The rungs do not interfere with the flattening of the railsnor do they interfere with the reforming of the rails into tubes. Toextend the ladder to its extended position, the U-strap 39 is releasedfrom engagement with the rung 15 and the storage reel rotated in therequired direction. As soon as the flattened portions are a shortdistance above the reel they will start to reform into the tubular formand by the time they reach the plate 26 they will have completelyreformed into the tubular rails 13, 14. In the transition phase theplate 27 gives support to the rails. When reformed, the plates 25, 26give support to the completely extended ladder. In reforming, onelongitudinal edge of each rail is allowed to jam between the other edgeof the rail and the rung, thus preventing further coiling and at thesame time supplying a degree of rigidity for the assembly.

In the structure illustrated in FIGURES 6 and 7, a plurality ofextensible-retractile units each unit being constructed as illustratedin FIGURES 1 to 5 inclusive are employed, with one rail of one unitcoiled around the contiguous rail of the adjacent unit to form a unitarystructure which is rigid and may be extended from a retracted positionand vice versa as often as required. For the purpose of illustratingthis modification the same will be described employing three unitsreleasably interconnected together to form a three sided tower. Thestruc ture illustrated comprises a first unit A, a second unit B and athird unit C, each unit being constructed in accordance with thepreceding description relative to FIG- URES 1 to 5.

The first unit A comprises a pair of longitudintally extensible rails13a, 14a connected together by a plurality of spaced rungs 15a; thesecond unit B comprises a plurality of longitudinally extensible rails13b, 1412 connected together by a plurality of spaced apart rungs 15b;and the third unit C comprises a plurality of longitudinally extensiblerails 13c, 14c connected together by a plu- Iality of of spaced apartrungs 150.

A support base 11a is provided for supporting the three units which basecarries three drums or reels 51, 52, 53, one for each of the units. Thefunction of the support base 11a and the drums 51, 52, 53 is similar tothe base and drum previously described in connection with FIG- URES 1 to5 inclusive. The base 11a for the three units is of triangular form inplan and comprises a bed plate 40, angle supports 41, 42, 43; atriangular shaped outer frame 44 supported by said supports 41, 42, 43and an inner central plate 74 carried on three uprights 73 fixed at thebottom end to base 40, the perimeter of the plate 62 being spacedinwardly from the inside edges of the outer frame to form three equallyspaced arcuate guideways 45, 46, 47 disposed at 60 to each other, saidguide- Ways being connected together by longitudinal slots 48, 49, 50.The said guideways and slots perform the same function as the slots 36,37, 38 and permit the unit to be 4 raised and lowered by the mechanismhereinafter described.

The mechanical mechanism for raising and lowering the unit comprises thethree sets of drums 51, 52, 53 one for each unit with the lower ends ofthe rails which form each unit fastened to their respective drum in amanner similar to that previously described relative to FIGURES 1 to 4inclusive. The drum 51 is rotatably supported by the uprights 41, 43;drum 52 is supported by the uprights 42, 43; and the drum 53 issupported by the uprights 41, 42. The drum 53 is illustrated as beingprovided with a manually operated crank 54 whereby the drum 53 can berotated in the desired direction for selectively extending or retractingthe units, and a brake 55 for locking the drum 53 against rotation. Abelt and pulley drive '56, 57, 58 provides a driving connection betweenthe drum 53 and the drum 52; and a belt and pulley drive 59, '60, 61provides a drive connection between drum 51 and the drum 52. Theelements referred to in the preceding sentence provides a means forrotating the three drums in unison which in turn extends or retracts thethree units in unison. It will be apparent that power means may beutilized to replace the crank 54.

The units are extended by rotating the drums which unwind the flattenedrails, and shortly after leaving the drums, the flattened portionsreform into rails and contiguous rails entwine with each other, forexample, the rail 13b in reforming into a tubular rail entwines with thereforming rail 14c and so on. On retracting the rails onto theirrespective drums, the entwined rails disengage as they flatten out.

It will be seen in FIGURE 7 that at each corner of the structure anoutside rail is coiled around an inside rail and the two longitudinaledges of the outside rail jam between the rung and the inside rail towhich this rung is attached. This jamming provides a degree of rigidityfor the assembly. To further ensure that there will be no longitudinalrelative movement between the inner and outer rails which are coiledinside one another the top ends of the interengaged rails may befastened together by rivets 62, 63, 64. These rivets also ensure thatall the rails will be moved in unison when the drums are rotated toextend or retract the units.

In the present embodiment the upper ends of the rails are permanentlyentwined to have the ladder readily available for use. However, someapplications may require that the rails be completely separated whenwound up in which case, at the start of the unwinding to extend therails, the initial entwinement of the respective rails can be effectedby manual manipulation or by some suitable guide means.

What I claim as new and desire to protect by Letters Patent of theUnited States is:

1. An extensible-retractile structure comprising in combination:

(a) a pair of longitudinally extensible-retractile rails of tubularshape when extended and of fiat form when rolled up into a roll, eachrail comprising a thin strip of resilient material of substantial lengthpreformed to coil about its longitudinal axis to form the tubular shapewhen extended from the roll; and

(b) transverse rungs, in spatial relationship, connected to said railsto form a unitary structure without inter: fering with the rolling up ofthe rails into the roll.

(c) and stop means preventing relative movement both longitudinally andcircumferentially between overlapping portions of each tubular rail tothereby prevent lateral distortion or deflection of the walls of thetube under load.

2. An extensible-retractile structure according to claim 1 in which saidstop means comprise wedging members formed by the opposing faces of therungs and the tubular rails to which the rungs are attached into whichthe longitudinal edges of the encircling tubular rails jam.

3. An extensible-retractile structure comprising in combination:

(a) a base member;

(b) structure support members carried by the base;

(c) a rotatable storage reel supported by said base member;

((1) a pair of longitudinally extensible-retractile rails of tubularshape when extended and of fiat form when retracted, each railcomprising a thin strip of resilient material of substantial lengthpreformed to coil about its longitudinal axis to form the tubular shape;the lower end of each rail being secured in a flat condition to the reelthereby permitting the rails to be unwound thereon when retracted:

(e) transverse rungs, in spatial relationship, connected to said railsto form a unitary structure without interfering with the Winding of therails on the reel;

(f) said rails, after assuming tubular form, being slidably supported inan upright load carrying position by the said support members; and

(g) and stop means preventing relative movement both longitudinally andcircumferentially between overlapping portions of each tubular rail tothereby prevent lateral distortion or deflection of the walls of thetube under load;

(h) means for rotating said storage reel whereby on turning the reel inone direction the fl-at thin rails are extended in tubular shape and onturning the reel in the opposite direction the rails, as they approachthe reel, assume a fiat condition on said reel.

4. An extensible-retractile structure according to claim 3 having loadcarrying releasable means locking said rails against downward movementunder the force of an applied load when in an extended position.

5. An extensible-retractile structure according to claim 3 in which theladder support members comprise a plurality of transverse frame membersin parallel spaced relationship, said members having vertically alignedpassages in which the tubular rails are slidably engaged and supported.

6. An extensible-retractile structure according to claim 3 in which saidstop means comprises wedging members formed by the Opposing faces of therungs and the tubular rail to which the rungs are attached, into whichmembers a longitudinal edge of the encircling portion of the tubularrail jams.

7. An extensible-retractile structure comprising in combination:

(a) at least three pairs of longitudinally extensibleretractile rails oftubular shape when extended and of flat form when rolled up into rolls,each pair being wound on and extended from a separate roll, each rail ofeach pair of rails comprising'a thin strip of resilient material ofsubstantial length preformed to coil about its longitudinal axis to formthe tubular shape when extended from the rolls;

(b) transverse rungs in spatial relationship connected to each pair ofsaid rails;

(c) one rail of each pair being coiled around the contiguous coiled railof the adjacent rail of another pair when said rails are extendedthereby forming a closed geometric figure and separated therefrom whenwound into rolls;

(d) and stop means preventing relative movement both longitudinally andcircumferentially between overlapping portions of each tubular rail tothereby prevent lateral distortion or deflection of the walls of thetube under load.

8. An extensible-retractile structure according to claim 7 in which saidstop means comprises wedging members formed by the opposing faces of therungs and the tubular rail to which the rungs are attached, into whichmembers a longitudinal edge of the encircling portion of the tubularrails jams.

9. An extensible-retractile structure comprising in combination:

(a) a base member;

(b) structure support members carried by the base;

(0) a plurality of operatively connected rotatable storage reelssupported by said base member;

(d) a plurality of longitudinally extensible-retractile rails of tubularshape when extended and of fiat form when retracted, said rails beingarranged in pairs and corresponding in number to the number of reels,each rail of each pair of rails comprising a thin strip of resilientmaterial of substantial length preformed to coil about its longitudinalaxis to form the tubular shape, the lower ends of each pair of railsbeing secured in a fiat condition to a reel thereby permitting the railsto be wound thereon when retracted;

(e) transverse rungs in spatial relationship connected to each pair ofsaid rails;

(f) one rail of each pair being coiled around the contiguous tubularrail of the adjacent rail of another pair when said rails are extendedthereby forming a closed geometric figure and separated therefrom whenwound on said reel;

(g) said tubular rails being slidably guided and supported in an uprightload carrying position by the said support members;

(h) each pair of rails and rungs associated therewith forming anextensible-retractile rigid column in its extended position;

(i) drive means operatively interconnecting said reels whereby, onturning the reel in one direction all of the rails and associated rungsare moved in unison to an extended position as a unit and on turning thereels in the opposite direction the rails are uncoiled as a unit andassume a flat condition on said reels.

10. An extensible-retractile structure according to claim 9 in which theladder support members comprise a plurality of transverse frame membersin parallel spaced relationship, said members having vertically alignedpassages in which the tubular rails are slidably engaged and supported.

11. An extensi-ble-retractile structure according to claim 9 havingstops limiting the coiling of the rails about the longitudinal axis.

12. An extensible-retractile structure according to claim 11 in whichsaid stops comprise wedging members formed by the opposing faces of therungs and the tubular rails to which the rungs are attached, into whichthe longitudinal edges of the encircling tubular rails jam.

References Cited UNITED STATES PATENTS 2,130,993 9/1938 Dubilier l82412,269,364 1/1942 Farrand 18241 2,799,368 7/1957 Alter 1824l 3,144,104-8/1964 Weir 52108 3,252,173 5/1966 Robinsky 52-108 3,258,800 7/1966Robinsky 52-408 FOREIGN PATENTS 350,790 6/ 1905 France.

REINALDO P. MACHADO, Primary Examiner.

